Hello

I am installing a dual boot Arch Linux/Windows 10 OS in UEFI mode using a GPT partition table. Windows 8 updated to Windows 10 was installed first.

How I Partitioned:
Sda1 Windows Recovery
Sda2 EFI (Windows Created EFI partition - mounted to /boot
Sda3 Microsoft Reserved
Sda4 Microsoft Basic Data
Sda5 Windows Recovery Environment
Sda6 EFI System (I thought I needed a linux boot partition as well when I created it)
Sda7 Linux Swap
Sda8 Root File System
Sda9 Home Linux File System


At the point where I run Os-Prober I get:
/dev/sda2@/EFI/Microsoft/Boot/bootmgfw.efi:Windows Boot Manager: Windows:efi
[554.587094]EXT4-fs (sda3): VFS: Can't find ext4 filesystem
[554.507054]EXT4-fs (sda3): VFS: Can't find ext4 filesystem
[554.588589]EXT4-fs (sda3): VFS: Can't find ext4 filesystem
[]FAT-fs (sda3): bogus number of reserved sectors
[]FAT-fs (sda3): bogus number of reserved sectors
[]ntfs: (device sda3): read_ntfs_boot_sector(): Primary boot sector is invalid
[]ntfs: (device sda3): read_ntfs_boot_sector(): Mount option errors=recover not used. Aborting without trying to recover.
[]ntfs: (device sda3): ntfs_fill_super(): Not an ntfs volume.
[]ufs: You didn't specify the type of your ufs filesystem
[]
[]mount -t ufs -o ufstype=sun|sunx86|44bsd|ufs2|5xbsd|old|hp|nextstep|nextstep-cd|openstep ...
[]
[] >>>WARNING<<< Wrong ufstype may corrupt your filesystem, default is ufstype=old
[]ufs: ufs_fill_super():bad magic number

Tried grub-mkconfig -o /boot/EFI/grub/grub.cfg after this with no success
I was also getting the error:
WARNING: Failed to connect to lvmetad: No such file or directory. Falling back to internal scanning.
which I fixed by editing the /etc/lvm//lvm.conf file and changing use_lvmetad=0
I believe Secure boot is turned off
I also Turned off Windows Fast boot

There are so many errors I am not sure where to begin?
If anyone can point me in any direction it would be greatly appreciated.
If you need any more information let me know!

Thanks!

first of all, using os-prober by itself does nothing but output to the terminal.
but grub-mkconfig will use it when it is installed.
in any case, it is normal for os-prober to throw warnings and even errors.
the only way to see if it worked is to reboot.
which brings me to the more important question:
why do you say with no success? how exactly did it not work? did you reboot to test it?

The UEFI microcode looks for the EFI partition. Having two of them is just asking for trouble.

Delete all the Arch partitions, and start again, using the EFI partition that already exists - Arch will create its own directory as needed. All explained in the wiki and install guide.
All this is complex enough what with various hardware vendors doing the microcode differently. Don't make it harder than it needs to be.

Thank you for your answers

Yes I rebooted to test it and only have the option to boot into linux.
The same errors appear in the os-prober section when I run grub-mkconfig...

I might try a different bootloader as I read that Grub can have errors with dual booting.

sygoo i quickly reformatted the partition as a linux filesystem and reran OS-Prober which delivered the same errors.
I will retry installing ASAP

i SHOULD ALSO MENTION, I'm a total so if the answer is 'You're doing it wrong' I can live with that lol

I suggested deleting (all) the Arch partition(s) - it's the partition id that's the concern.

As a newbie, Arch could be a bit of a challenge. Usually do-able, but tuff.
I'd suggest you give up on Arch for now (delete the Arch partitions), and try a distro that has good UEFI install support - say Mint, or Ubuntu (on which Mint is based). When you get that working as you want, add Arch - Leave Mint there so you have a working system to fallback to. Leave some space when you install Mint/Ubuntu/whatever. KISS.

The challenge is half the appeal
Will try deleting all and reinstalling

Thanks!